开展人造卫星的严格同步激光测距的建议

THE PROPOSAL OF STRICTLY SIMULTANEOUS SATELLITE LASER RANGING

鉴于目前最高水平的人卫激光测距仪已能达到1厘米的单次测量精度,如何在测站基线测量等应用方面充分发挥其潜力?本文建议开展人卫的严格同步激光测距,要求各测站的激光发射时刻严格地由计算机控制,使得各站的激光脉冲在特定时刻(如整秒或十分之一秒)尽可能同步到达卫星。目前广泛使用的主被动锁模激光器,同步时刻误差可达到10微秒(均方差)。本方法获得的全部观测资料除了适用于普遍应用的动力解之外,还有可能得到严格的几何解,而不必采用数学平滑和内插技术,因而在测定远距离站间基线方面将有希望达到5毫米精度。

In view of several 1 cm range accuracy (for single measurement) are now operational, how to exploit this high accuracy and to obtain ground baselines between laser stations with the same or better accuracy? A proposal of synchronized laser ranging to artificial satellites from different stations is presented in this paper. In this operational mode, the laser firing epoch at each station should be strictly controlled by computers so that all laser pulses transmitted from different stations arrive at a satellite at certain moments (such as seconds, or tenth of second) with a minimum time uncertainty (10 microseconds can be obtained for present passive mode-locked lasers). All full-rate range data attained in this mode can be analysed by dynamic technique as usual. Besides, based on the 3-D Multilateration method [7], a strictly geometric solution without polynomial smoothing and complex interpolation may be achieved, and 5mm accuracy baselines between laser stations could be obtained in near future.